I just received a new answer from SIGMA-Photo Korea.
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At first, we confirmed about this problem from the NIKON-Imaging Korea.
The problem you suggested is not a rare problem, and also we already knew about this.
This is not only for your lens(24-35), it's related with all lenses from our company.
In general, EXIF information of the images are collected by the camera body and displayed by the viewer program.
So, when the viewer program is changed, the displayed informations can be changed, too.
You said that another 3rd party lens, SIGMA 30mm f/1.4, is well displayed from the viewer program.
We tested about this, and the View NX (Nikon software) shows no brand name, only the 30/1.4G (Nikorr lens with similar specifications).
In addition, the Photoshop didn't recognizes our 30mm f/1.4 lens.
Maybe, this problem depends on the update status of the viewer program.
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